In general, a roll-shaped conductive elastic member or a conductive elastic roller is frequently used as a developing roller, a charging roller, a toner feed roller, a transfer roller, a paper feed roller, a cleaning roller, a pressure roller for fixing or the like in an image forming apparatus of an electro-photographic system such as a copying machine, a facsimile, a laser beam printer (LBP) or the like. Typically, the conductive elastic roller comprises a shaft member journaled at both longitudinal end portions thereof and at least one elastic layer disposed on an outside of the shaft member in a radial direction.
As the shaft member of the conductive elastic roller are used various resins such as engineering plastics and so on in addition to metals such as iron, stainless and so on. On the other hand, as the elastic layer of the conductive elastic roller are used various thermosetting resins such as thermosetting urethane resin and so on. The roller is produced by charging a resin material into a mold having a desired cavity form and curing the resin material under heating (see JP-A-2004-150610).